Effect of Al concentration on pseudoelasticity in Fe3Al single crystals

Pseudoelasticity in Fe₃Al single crystals with different Al contents was investigated focusing on the dislocation configuration and the ordered domain structure. Giant pseudoelasticity only appeared in the D0₃-ordered Fe₃Al single crystals, while the B2-ordered crystals and those with the disordered phase exhibited small strain recovery. The amount of shape recovery in the D0₃-ordered crystals showed a maximum near 23.0at.%Al and decreased with increasing deviation from this Al concentration. In the D0₃ phase at 22.0–25.0at.%Al, 1/4[1 1 1] superpartial dislocations moved individually dragging the nearest-neighbour antiphase boundaries (NNAPB), while couplets of the superpartials were observed to bow out, dragging the next-nearest-neighbour antiphase boundaries (NNNAPB) in Fe–28.0at.%Al. In Fe–22.0–25.0at.%Al single crystals, the NNAPB pulled back the superpartials to decrease its energy during unloading, resulting in the giant pseudoelasticity. In contrast, the surface tension of the NNNAPB was lower than that of the NNAPB, leading to the small strain recovery in Fe–28.0at.%Al.     

Load‐bearing control of slender bridges

An active control of the load‐bearing capacity of slender bridges is treated in the present paper. Interactive conditions in ultimate response are considered. A numerical treatment of the occurring/appearing non‐linear problems is made using the updated Lagrangian formulation of motion. Each step of the iteration approaches the solution of linear problem and the feasibility of the parallel processing FETM‐technique with adaptive mesh refinement and substructuring for the analysis of ultimate behaviour of bridges is established. Application to an actual bridge is submitted in order to demonstrate the efficiency of the procedures suggested. Copyright © 2004 John Wiley & Sons, Ltd.     

A novel method of suppressing the inrush current of transformers by using a series‐connected voltage‐source PWM converter

This paper proposes a novel method of suppressing the inrush current of transformers. A small‐rated voltage‐source PWM converter is connected in series to the transformers through a matching transformer. As the connected PWM converter serves as a resistor for the source current, no inrush phenomena occurs. The required rating of the PWM converter, which serves as the damping resistor for the inrush phenomena, is 1/400 that of the main transformers in single‐phase circuits. In three‐phase circuits, it is 1/900. The basic principle of the proposed method is discussed. Digital computer simulation is implemented to confirm the validity and excellent practicability of the proposed method using the PSCAD/EMTDC. A prototype experimental model is constructed and tested. The experimental results demonstrate that the proposed method can perfectly suppress the inrush phenomena. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(4): 56–65, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20174     

THE ROLE OF INTERFACIAL PHENOMENA IN A LIQUID-LIQUID REACTION SYSTEM: EXTRACTION OF PROPANOIC ACID BY TRIOCTYLAMINE

The kinetics of extraction of propanoic acid from water to isobulanol by reaction with trioctylamine have been investigated. Mass transfer was modelled by extending the approach used in absorption with chemical reaction, as it is usually done for liquid-liquid reactions. The presence of the amine, however, gave rise to phenomena that cause this method to fail, producing inconsistent results. In order to explain these data, the presence of relevant interfacial phenomena must be supposed.     

Raman microscopy of fibres and composites

Some of the progress made in using Raman microscopy to examine the structure and micromechanics of polymer and inorganic fibres is reviewed. Examples of how the technique has been used to verify some of the theories of composite reinforcement are then given. Finally, a specific example of how Raman microscopy has been used, in conjuction with other approaches, to understand the micromechanics of the microbond test, which is often used to measure interfacial shear strength in composite systems, is presented.     

非接触感应电能传输系统的频率分叉现象及移相控制策略

以原副边均采用串联补偿方法进行研究,分析了非接触感应电能传输系统的高阶数学模型,探究了频率分叉实质,利用Matlab进行曲面仿真,了解系统的频率分叉现象,从而得出较为合理的补偿方案。分析了发生频率分叉时,如何选择优化的工作频率,采用移相控制的方式使系统得到稳定的输出。     

A novel adaptive HBCC technique for three-phase shunt APF

This paper proposes an important improvement of the hysteresis band current control (HBCC) technique for three-phase shunt active power filter (APF) to eliminate harmonics and to compensate the reactive power generated by three-phase rectifier. In this technique, a simple and quick prediction of the hysteresis band is added to a phase-locked-loop (PLL) control to ensure constant switching frequency and synchronization of modulation pulses independently on system parameters. This allows the advantages of quick response, good current tracking accuracy and minimal ripple in three-phase systems. This technique is robust and it is characterized by the simplicity, this aspect is very significant for a practice realization because it constitutes the factors which determine the cost and the reliability of industrial assembly. The proposed technique determines the switching signals of the three-phase shunt APF and the algorithm which is based on the dc bus capacitors voltage regulation using proportional-integral (PI) controller is used to determine the suitable current reference signals. The behavior of the proposed technique has been fully verified by digital simulation, where the obtained results show that the proposed technique can improve shunt APF performances noticeably.     

电力电子变换器非线性混沌现象及其应用研究

电力电子变换器混沌现象是一个必须加以重视的问题,它的研究一方面将深刻认识电力电子变换器的本质,分析一些以往无法解释的现象,如不规则的电磁噪声、系统运行的不稳定工作状态;另一方面将基于混沌现象提出新的设计方法和控制策略,实现现有电力电子变换器无法达到的性能.为此,本文将从确定性运动、随机运动角度分析电力电子变换器混沌现象研究的必然性,明确电力电子变换器混沌现象的研究目的.文中主要以DC-DC变换器为研究对象,对电力电子变换器混沌现象的基本类型进行分析和综合,由此展望对电力电子变换器混沌研究的发展和未来应用的前景.     

从“善有恶报”看当今社会的伦理困境

分析各种＂善有恶报＂的不道德现象,从功利主义的道德选择和道德律令的失效着手,深入剖析当今社会的伦理困境,在此基础上提出解决现存道德问题的相应对策。     

粘性联轴器转矩特性研究

建立了粘性联轴器转矩特性及换热的数学模型。给出了一种粘性联轴器转矩特性的计算方法,该方法综合考虑了硅油温度、剪切率对硅油粘度的影响以及硅油填充率对峰值特性产生时间的影响。通过实验验证,可定量分析粘性联轴器的各种影响因素,为粘性联轴器的设计、应用和研究提供了理论基础。